Commands by ariver (2)

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find both total size and number of files below any given svn directory
afaik, svn doesn't have a good, scriptable way of telling you these two basic pieces of information.

Create a file of repeated, non-zero
dd can be used with /dev/zero to easily create a file of all zero-bytes. Pipe that through tr and use octal conversions to change the byte values from zero to 0xff (octal 0377). You can replace 0377 with the byte of your choice. You can also use \\0 and \\377 instead of the quoted version.

List open files that have no links to them on the filesystem
I have come across a situation in the past where someone has unlinked a file by running an 'rm' command against it while it was still being written to by a running process. The problem manifested itself when a 'df' command showed a filesystem at 100%, but this did not match the total value of a 'du -sk *'. When this happens, the process continues to write to the file but you can no longer see the file on the filesystem. Stopping and starting the process will, more often than not, get rid of the unlinked file, however this is not always possible on a live server. When you are in this situation you can use the 'lsof' command above to get the PID of the process that owns the file (in the sample output this is 23521). Run the following command to see a sym-link to the file (marked as deleted): $ cd /proc/23521/fd && ls -l Truncate the sym-link to regain your disk space: $ > /proc/23521/fd/3 I should point out that this is pretty brutal and *could* potentially destabilise your system depending on what process the file belongs to that you are truncating.

extracts 64 bytes of random digits from random lines out of /dev/random sent to stdio
Use this the next time you need to come up with a reasonably random bitstring, like for a WPA/WPA2 PSK or something. Takes a continuous stream of bytes coming from /dev/urandom, runs it through od(1), picking a random field ($0 and $1 excluded) from a random line and then prints it.

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Opens vi/vim at pattern in file
Open up vi or vim at the first instance of a pattern in [file]. Useful if you know where you want to be, like "PermitRootLogin" in sshd_config. Also, vi +10 [file] will open up a file at line 10. VERY useful when you get "error at line 10" type of output.

Using NMAP to check if a port is open or close
Using NMAP to check to see if port 22(SSH) is open on servers and network devices.

Search some text from all files inside a directory

Decrypt passwords from Google Chrome and Chromium.
Read this before you down voting and comment that it is not working -> Wont work on latest versions ~75> since database file is locked and has to be decrypted. This is useful if you have an old hdd with a chrome installation and want to decrypt your old passwords fast.

Replace spaces in filenames with underscores


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